How Do We See Color?

Look at the lemon — YELLOW and round! Look at the sky — BLUE all around! Look at the strawberry — RED RED RED! How does that color get into your head?

Way in the back of your eyeball there Sits a screen called the RE-TI-NA there! Tiny little cells stand up like trees — Color catchers, they wave in the breeze!

Three kinds of catchers! Just three! Just three! RED catchers, GREEN catchers, BLUE — that's me! Each one lights up when its color flies in — Three little signals begin to begin!

Red, green, blue — three signals run! Up the wire to the brain like a starting gun! The brain reads the mix — bright? dim? loud? soft? — And paints what you SEE in the world aloft!

Yellow lemon? RED says YES! GREEN says YES! BLUE stays quiet — Brain says YELLOW! Time to try it! Purple grape? RED says YES! BLUE says YES! GREEN sits down — Brain says PURPLE — pass it around!

Three little cones — that's the whole game! Every color the world's got is in the same frame! Three signals MIXED in the brainy back room — Make a rainbow of colors that shine and bloom!

Three! Three! Three little cones! Mixing every shade in the world we've known! Red plus green plus blue is WHITE! Take any one out — you change the sight!

How do we know? How do we know? A man named Thomas Young, two hundred years ago, Sat with his pencil in eighteen-oh-two And said, "I bet there's only THREE — not a few!"

He didn't have a microscope to peek inside, He just looked at how colors mixed and slid — And he reasoned: THREE catchers is all you need To plant every color in every kid's seed!

Years went by — scientists peeked at the eye, Found three kinds of cones, just like he said, my! Red ones, green ones, blue ones too — Thomas Young's hunch turned out to be true!

Three! Three! Three little cones! Mixing every shade in the world we've known! A lemon, a grape, a strawberry sky — Three signals racing up the wire to the eye!

Look at your screen — get up real near — The pixels are RED and GREEN and BLUE, dear! The TV builds color the same little way — Three lights, three signals — that's the play!